The present invention relates to a drive system, and more particularly to a drive system having an electric motor with a brake and encoder.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
A drive system of this type is suitable for a production machine, for example a milling machine, a turning machine, or the like, but also for robots, conveyors etc. This type of drive system is also referred to as servo drive and typically have an electric motor with a brake, and a power converter which is connected to the electric motor by way of a plurality of cables.
In electric servo drives, transducers or encoders having a digital interface in the motor are normally used to date for sensing the position of the electric motor. These encoders are connected via an encoder line which contains the voltage supply conductors and the conductors required for transfer of data.
Besides data lines and voltage supply lines for the encoder, so-called power lines are provided for transfer of electrical energy to the electric motor. In addition, control lines are provided for the brake which is normally operated by a DC voltage (for example 24 V DC). For the most part, the lines between converter and electric motor are grouped in two cables which run in parallel and which require space in the cable conduit and the cable carrier. This is disadvantageous.
It is known to use only one cable between power converter and electric motor, wherein the electric motor has a brake and an encoder. With the introduction of the “HIPERFACE DSL” encoder interface by the Sick-Stegmann company, voltage supply, and data communication with the encoder can be realized via only two twisted-pair lines. Such a line can be very thin and integrated together with the power lines into a single cable. While a user needs to connect only a single cable (generally referred to as line assembly), which includes the encoder lines, between power converter and motor, there is still a need on the electric motor for a special connector which accommodates the additional contacts for the two communication cores. Such connectors are commercially available in connector sizes of up to 1.5. Beyond that, there is however no corresponding connection technology.
It would therefore be desirable and advantageous to provide an improved drive system which obviates prior art shortcomings and has a simplified connection technology.